Piper Autocontrol IIIB

Flew to dinner today with an outside temp of 10F. Auto pilot worked OK on the
trip out (plane came out of a 45F hanger). Parked for dinner for about 2
hours. The autopilot didn't work on the way back. You could feel the clutch
take hold but no corrective action to follow the bug. Simple roll control
didn't respond either. Well, about 20 minutes into the flight home, it started
to work. OK all the way home.

So, is it on its last leg and I should pull it and see if I can get it fixed?
Fixed where? Or is the low temperture (it was outside for 2 hours in 10F) the
problem? If it's low temp, I'm tempted to let it go since I don't often fly
there.

Chuck

Chuck, this is EXACTLY what mine did -- right before my attitude indicator
went belly up.

Then, again, a month later when the DG failed.

My advice: wait. It may not be the autopilot itself.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"PaulaJay1" wrote in message
...
Flew to dinner today with an outside temp of 10F. Auto pilot worked OK on
the
trip out (plane came out of a 45F hanger). Parked for dinner for about 2
hours. The autopilot didn't work on the way back. You could feel the
clutch
take hold but no corrective action to follow the bug. Simple roll control
didn't respond either. Well, about 20 minutes into the flight home, it
started
to work. OK all the way home.

So, is it on its last leg and I should pull it and see if I can get it
fixed?
Fixed where? Or is the low temperture (it was outside for 2 hours in 10F)
the
problem? If it's low temp, I'm tempted to let it go since I don't often
fly
there.

Chuck

In article 3ycMb.23987$8H.56750@attbi_s03, "Jay Honeck"
writes:

Chuck, this is EXACTLY what mine did -- right before my attitude indicator
went belly up.

Then, again, a month later when the DG failed.

My advice: wait. It may not be the autopilot itself.
--

The AI and DG were overhauled 1250 hours (and 7 years) ago. That just might be
the problem. I wait and see what happens mext flight.

Chuck
Archer 2185B

(PaulaJay1) wrote in
:

Flew to dinner today with an outside temp of 10F. Auto pilot worked
OK on the trip out (plane came out of a 45F hanger). Parked for
dinner for about 2 hours. The autopilot didn't work on the way back.
You could feel the clutch take hold but no corrective action to follow
the bug. Simple roll control didn't respond either. Well, about 20
minutes into the flight home, it started to work. OK all the way
home.

I have to disagree with Jay. If the roll control wouldn't do anything,
then it's not the DG or AI. It's either in the autopilot "computer"
(the part in the panel) or the motor (okay, a cable problem is possible,
but unlikely).

The clutch isn't much, a simple solenoid connected through the autopilot
left hand switch. Take every resistor and transistor and capacitor out
of the circuit the clutch would still work. But beyond that, lots of
thing could stop the "computer" from working. Just kill the reference
oscillator would do it. [Okay, if the excitation coil in BOTH the DG
and AI went out (or only one, if their is a NAV Coupler in between),
then that could do it.]

I'm guessing a cold solder joint or a capacitor gone temp. sensitive.

Next time you are playing around in those types of temperatures, take
the computer inside with you (it comes out fairly easily). See if the
failure repeats.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

If you aren't too far away, the best service is at Century Systems in
Mineral Wells, TX (MWL) pretty close to DFW. We flew down and had them fix
our IIIB years ago for a reasonable price and they did a great job. They
even hooked up the Nav 2 selector to our M1 Loran.

"PaulaJay1" wrote in message
...
Flew to dinner today with an outside temp of 10F. Auto pilot worked OK on
the
trip out (plane came out of a 45F hanger). Parked for dinner for about 2
hours. The autopilot didn't work on the way back. You could feel the
clutch
take hold but no corrective action to follow the bug. Simple roll control
didn't respond either. Well, about 20 minutes into the flight home, it
started
to work. OK all the way home.

So, is it on its last leg and I should pull it and see if I can get it
fixed?
Fixed where? Or is the low temperture (it was outside for 2 hours in 10F)
the
problem? If it's low temp, I'm tempted to let it go since I don't often
fly
there.

Chuck

In article et, "McGregor"
writes:

If you aren't too far away, the best service is at Century Systems in
Mineral Wells, TX (MWL) pretty close to DFW. We flew down and had them fix
our IIIB years ago for a reasonable price and they did a great job. They
even hooked up the Nav 2 selector to our M1 Loran.

"PaulaJay1" wrote in message
...
Flew to dinner today with an outside temp of 10F. Auto pilot worked OK on
the
trip out (plane came out of a 45F hanger). Parked for dinner for about 2
hours. The autopilot didn't work on the way back. You could feel the
clutch
take hold but no corrective action to follow the bug. Simple roll control
didn't respond either. Well, about 20 minutes into the flight home, it
started
to work. OK all the way home.

So, is it on its last leg and I should pull it and see if I can get it
fixed?
Fixed where? Or is the low temperture (it was outside for 2 hours in 10F)
the
problem? If it's low temp, I'm tempted to let it go since I don't often
fly
there.

Chuck

It is not very close (I'm in Ohio) but I"ll keep it in my bag of tricks. Might
be flying in that area before the winter is over.

I went out to the plane yesterday. Hanger temp about 40F. Autopilot worked
fine. My electronics guy at KCAK says watchful waiting. May be harbinger of
things to come or may have been that way for years and won't get worse.

Chuck

PaulaJay1 wrote:



It is not very close (I'm in Ohio) but I"ll keep it in my bag of tricks. Might
be flying in that area before the winter is over.

I went out to the plane yesterday. Hanger temp about 40F. Autopilot worked
fine. My electronics guy at KCAK says watchful waiting. May be harbinger of
things to come or may have been that way for years and won't get worse.



Unfortunately, the situation is not unlike one I faced a few years ago.

The inescapable fact is, these autopilots are getting old. They're
tired, and they start acting up. Doing their job gets harder and harder
for them to do properly.

The factory is the court of last resort, obviously, but when I
approached them for service on my autopilot, I was told they were no
longer able to get parts, and servicing my autopilot was no longer an
option.

They offered to sell me a used control unit, but I declined, based on
the fact that I'd still be flying around with an autopilot that no one
could service when it needed it.

Ultimately, I had an Stec System 55 installed.

century (mineral wells) doesn't work on the old ones anymore
(unless they have started back up.) be sure to call & check before
you go.

however, "autopilots central" in tulsa still works on them (last time
i checked.) they are very knowledgeable about the century's,
probably the best in the business as century won't do them
anymore.

http://www.sparksaviationcenter.com/

an intermittent like you have frequently is just a bad connection
in one or both of the connectors that go from the gyros to the
"computer". these are small round connectors with some odd
number (5? 7?) of pins. the male pins are very small diameter,
and the female receptacles for them are sort of a split socket
(envision the petals of a tulip bloom). these "petals" get spread
out and don't make good contact. if you have real steady hands,
you can disconnect the cable, and with a needle _gently_ bend
the petals back together to make good contact. if i remember
correctly, the male pins are on the back of the gyro, and the
female pins are in the cable, so after disconnecting the cable
hangs down a little to give you more room to work.

i used to do this fairly frequently (every 6-8 months or so). then
i replaced the century with an stec-30, do i don't have to do it
any more. :-)

hth,

g_a



(PaulaJay1) wrote in message ...
In article et, "McGregor"
writes:

If you aren't too far away, the best service is at Century Systems in
Mineral Wells, TX (MWL) pretty close to DFW. We flew down and had them fix
our IIIB years ago for a reasonable price and they did a great job. They
even hooked up the Nav 2 selector to our M1 Loran.

"PaulaJay1" wrote in message
...
Flew to dinner today with an outside temp of 10F. Auto pilot worked OK on
the
trip out (plane came out of a 45F hanger). Parked for dinner for about 2
hours. The autopilot didn't work on the way back. You could feel the
clutch
take hold but no corrective action to follow the bug. Simple roll control
didn't respond either. Well, about 20 minutes into the flight home, it
started
to work. OK all the way home.

So, is it on its last leg and I should pull it and see if I can get it
fixed?
Fixed where? Or is the low temperture (it was outside for 2 hours in 10F)
the
problem? If it's low temp, I'm tempted to let it go since I don't often
fly
there.

Chuck

It is not very close (I'm in Ohio) but I"ll keep it in my bag of tricks. Might
be flying in that area before the winter is over.

I went out to the plane yesterday. Hanger temp about 40F. Autopilot worked
fine. My electronics guy at KCAK says watchful waiting. May be harbinger of
things to come or may have been that way for years and won't get worse.

Chuck

How often do you fly in weather this cold? I would believe that the
clutch disk is just cold and did not have the friction required to
follow the commands. I had this happend in my 180 but not due to cold
but due to dust/dirt. Sometimes the clutch just loses its capability to
turn the thing. I sent it back to Stec and they fixed it.

Sandy Mustard

PaulaJay1 wrote:

Flew to dinner today with an outside temp of 10F. Auto pilot worked OK on the
trip out (plane came out of a 45F hanger). Parked for dinner for about 2
hours. The autopilot didn't work on the way back. You could feel the clutch
take hold but no corrective action to follow the bug. Simple roll control
didn't respond either. Well, about 20 minutes into the flight home, it started
to work. OK all the way home.

So, is it on its last leg and I should pull it and see if I can get it fixed?
Fixed where? Or is the low temperture (it was outside for 2 hours in 10F) the
problem? If it's low temp, I'm tempted to let it go since I don't often fly
there.

Chuck